The invention relates to diaphragm blades for iris diaphragms of optical instruments, in which each diaphragm blade has a bearing pin and a control pin.
It is known to use cylindrical solid or hollow rivets as bearing pins and control pins for diaphragm blades. The disadvantage of such a pin is that production tolerances, both between the bearing bore and the bearing pin, and between the control cam and the control pin, can give rise to undesired play. This results in lost motion which is particularly troublesome when making small adjustment movements.
In order to overcome this disadvantage, it has therefore been proposed, for example in German Pat. No. 1,058,834, to design a bearing pin and a control pin as a cone, the greatest diameter of which is greater than the clearance of the control cam or greater than the diameter of the bearing bore.
However, a general disadvantage of both bearing pin and control pin forms, is that only with some effort can they be fixed perpendicularly to the diaphragm blade. This is neccessary, however, in order to prevent an increased friction between the bearing and the control elements resulting from tilting of the bearing pin or control pin in the bearing bores or control cams of the iris diaphragm mount and demanding increased actuating forces for the diaphragm movement.